Go to Dashboard and you'll see Users. Click Users > Add New.

Fill out the details: Username, email address, first and last name, website then generate a password by clicking 'show password'

Then choose the role that is necessary. 

Here are the default roles in WordPress:

  • Administrator
  • Editor
  • Author
  • Contributor
  • Subscriber
  • Super Admin

If you have Woocommerce, there are additional roles: 

  • Shop Manager
  • Customer

When you're done, click 'Add New User'